JPH0869664A - Motor for driving disk - Google Patents

Abstract

PURPOSE: To form a motor to a thinner type and to make torque larger and a cost lower by detecting the magnetic flux of a magnet for a field via a magnetic material outside the range of the direct magnetic field and forming the magnetic material thinner than a Hall element. CONSTITUTION: The magnetic flux is generated in the magnet 5 for the field when electric power is supplied to the motor for driving a disk. This magnetic flux crosses a printed coil 3. At this time, the magnetic flux is transmitted to the position outside the range of the direct magnetic field of the magnet 5 from this position, i.e., the position on the outer side of the rotor 2 or the bracket 1, by which the intensity of the magnetic flux is detected by the Hall element 11 mounted in this part. The signal detected by the element 11 is transmitted to a control circuit, by which the printed coil 3 is energized in the order determined in accordance with the this signal. The magnetic flux from the magnet 5 crosses the coil 3 at the time when the magnetic flux flows toward an auxiliary yoke 6, by which the rotor 2 is rotated and the disk 10 mounted at the rotor 2 is rotated integrally with the rotor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor for driving a magneto-optical recording disk used in information equipment and the like. 1

[0002]

2. Description of the Related Art Generally, as an apparatus of this type, the invention disclosed in Japanese Patent Application Laid-Open No. 64-64165 is known. The device described in the publication, as shown in FIG.
A rotary shaft 23 is rotatably provided at the center of the disk-shaped shield 21 via a bearing 22, and a rotor 39 made of a non-magnetic material is fitted and attached to the other end of the rotary shaft 23.

Between the opposing surfaces of the shield 21 and the rotor 39, the printed board 29 is provided on the surface of the shield 21 side.
A plurality of stator coils 38 are fixed to the Hall element 28, and a Hall element 28 for detecting the strength of the magnetic flux is fixed to the central portion of one of the stator coils 38. On the other hand, a plurality of field magnets 26 are fixed to the surface of the rotor 39 so as to face the stator coil 38 and to have an axial gap.

The field magnet 26 rotates the rotor 39 by an electromagnetic action between the field magnet 26 and the stator coil 38, and the disk 34 is attached to the surface of the rotor 39 opposite to the surface on which the field magnet 26 is mounted. It also has the purpose of adsorbing and rotating the disk 34 integrally with the rotor 39.

[0005]

However, the Hall element 28 provided in the conventional disk drive motor described above.
Is arranged in the central portion of the coil 38 or in the direct magnetic field range of the field magnet 26 between the coils 38, so that an axial space for providing the Hall element 28 between the coils is required. Therefore, for example, even if the coil is formed thin such as a print coil (also referred to as a sheet coil), the Hall element 28 is thick, so that the space in the thickness direction cannot be reduced.

If a wide gap corresponding to the thickness of the Hall element 28 is provided between the coil and the field magnet, the magnetic flux crossing the coil is weakened by the wide gap and the torque of the motor is weakened. At the same time, there is a problem that the total length of the motor becomes longer due to the wider gap.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a disk drive motor which can be manufactured at a low cost by making the motor even thinner and increasing the torque.

[0008]

In order to achieve the above object, the present invention is directed to a stator coil fixed to a bracket and an axial gap between the stator coil and the surface of the stator coil. A rotor with a field magnet fixed to the disk. The rotor with the field magnet fixed is integrally fitted to the rotating shaft and rotates through a bearing to a bracket to which a stator coil is fixed. In a motor, a stator coil fixed to a bracket is formed on a print coil, and a field magnet and an auxiliary yoke are fixed to both sides of the print coil on the circumference of the rotor with an axial gap between them. The magnetic body is fixed to the printed coil side between the field magnet and the field magnet, and one end of the magnetic body is attached to the magnetic field range of the field magnet. The magnetic field magnet, the other end of which is extended from the field magnet toward the outer periphery to a position outside the range of the direct magnetic field of the field magnet, and which faces the side surface of the extended end of the magnetic body. It is characterized by being arranged with a Hall element for detecting the strength of the magnetic flux from the.

Alternatively, a paint containing magnetic powder as a main component is printed on the surface of the print coil from a position within the magnetic field range of the field magnet to a position outside the direct magnetic field, and a position outside the range of the direct magnetic field is printed. The Hall element is arranged facing the surface of the magnetic powder, or the outer diameter of the auxiliary yoke is expanded to a position outside the range of the direct magnetic field of the field magnet, and the hole is facing the surface of the expanded portion. Place the element.

[0010]

As a function of the first aspect, the magnetic flux can be detected at a position outside the range of the direct magnetic field of the field magnet through the magnetic body. Further, since the magnetic body can be formed thinner than the Hall element, the gap is narrowed accordingly.
Therefore, the disk drive motor can be made thin. Further, the torque of the motor increases due to the narrowing of the gap.

As an operation according to claim 2, by replacing the magnetic material in the case of claim 1 by printing a paint containing magnetic powder as a main component on the surface of the print coil, the magnetic powder formed by printing is Since the film thickness can be made thinner than that of the magnetic material, the disk drive motor becomes even thinner than in the case of claim 1, and the torque of the motor also increases.

As an operation according to claim 3, by expanding the auxiliary yoke to outside the range of the direct magnetic field of the field magnet, the expanded portion achieves the same object as in the case where the magnetic body is provided in claim 1. Therefore, it is not necessary to use a magnetic material or magnetic powder, and the disk drive motor becomes thinner than in the case of claim 2, and the motor torque increases.

[0013]

Embodiments of the present invention will be specifically described below with reference to the drawings. In each of the embodiments, common points will be denoted by common reference numerals and corresponding description will be omitted.

(Embodiment 1) FIGS. 1 to 4 show Embodiment 1 of the present invention, FIG. 1 is a sectional view of a disk drive motor, FIG. 2 is a plan view of a print coil portion in FIG. 1, FIG. FIG. 4 is an enlarged view of the Hall element fixing portion.

As shown in FIG. 1, the disk drive motor of the present invention has a basic structure in which a stator coil is formed on a print coil 3 (also referred to as a sheet coil), and both sides of the print coil 3 are opposed to each other. Then, the field magnet 5 and the auxiliary yoke 6 are arranged with an axial gap therebetween.

As shown in FIG. 2, the printed coil 3 has fan-shaped coil bodies 3a formed by printing on both sides of a resin substrate 3b having a circular upper portion formed in a square shape. The coil body 3a is formed by keeping it.
The surface of is coated with a coating to protect the surface. Note that the number of coil bodies 3a is not limited to the equal distribution of 6 places, but should be arranged corresponding to the number of magnetic poles of the field magnet 5.

As shown in FIG. 1, the print coil 3 is fixed to the end surface of the ring-shaped convex portion 1a formed on the outer peripheral portion of the bracket 1, and the rotary shaft 7 is provided at the center of the bracket 1. One end is rotatably provided via two bearings 8 and 9. On the other hand, the rotor 2 made of a non-magnetic material, to which the field magnet 5 and the auxiliary yoke 6 are fixed, is integrally press-fitted to the other end of the rotating shaft 7 so as to be rotatable together with the shaft 7. There is.

Further, the rotor 2 has a dish-shaped recess 2b formed on the surface opposite to the side to which the field magnet 5 is fixed, and a ring-shaped projection 2a (disk loading portion) formed on the outer periphery. There is. The center of the disk 10 is precisely fitted to the rotating shaft 7, the central thick portion of the disk 10 is allowed to fall into the dish-shaped recess 2b of the rotor 2 in a non-contact manner, and the outer peripheral side surface of the disk 10 is rotated. It is brought into contact with the end surface (disk loading surface) of the protrusion 2a. Further, a disk yoke 10a is fixedly provided on the disk 10 at the central circumferential surface on the rotor 2 side, and the disk yoke 10a is attracted to the rotor 2 side by the magnetic force of the field magnet. The outer peripheral side surface of the disk is strongly brought into contact with the end surface of the protrusion 2a of the rotor 2, so that the disk 10 is rotated integrally with the rotor 2.

A magnetic body 4 is arranged between the field magnet 5 having the above-mentioned structure and the printed coil 3, as shown in FIG. As shown in FIG. 2, the size of the magnetic body 4 on the plane is a width that can be fixed within the space between the coil bodies 3a of the print coil 3 and a magnetic field within the range of the direct magnetic field of the field magnet. Is press-molded to a length that can extend to a position outside the range, and is closely attached to the surface of the substrate 3b within the interval between the coil bodies 3a. Then, as shown in FIGS. 1 to 4, the Hall element 11 is located at a position away from the direct magnetic field of the field magnet, that is, at a position outside the rotor 2 or outside the bracket 1 on the opposite side of the print coil 3. And is attached so as to face the surface of the magnetic body 4.

In this case, the hall element 11 is mounted by soldering on a hall element wiring pattern (not shown) provided on the print coil 3 via a terminal (not shown).

As the operation of the disk drive motor having this structure, a magnetic flux is generated in the field magnet 5 by supplying electric power to the disk drive motor, and the magnetic flux crosses the print coil 3. At this time, the magnetic flux is transmitted to the magnetic body 4 located within the magnetic field range of the field magnet 5, and from this position is outside the range of the direct magnetic field of the field magnet 5, that is, outside the rotor 2 or the bracket 1. By being transmitted to the position, the strength of the magnetic flux is detected by the Hall element 11 attached to that portion. By transmitting the signal detected by the hall element 11 to the control circuit, the control circuit energizes the print coil 3 in the order determined based on the signal. Then, the magnetic flux from the field magnet 5 is applied to the auxiliary yoke 6
The rotor 2 is rotated by traversing the print coil 3 as it flows toward, and the disk 10 mounted on the rotor 2 is rotated integrally with the rotor 2.

In this case, the disk yoke 10a provided on the disk 10 is attracted to the rotor 2 side by the field magnet 5, and the magnetic body 4 is arranged between the coil bodies 3a of the print coil 3. As a result, the magnetic flux traversing the print coil 3 is not disturbed by the disk yoke 10a and the magnetic body 4.

According to this embodiment, the magnetic flux can be detected at a position apart from the direct magnetic flux of the field magnet 5 via the magnetic body 4. Further, since the magnetic body 4 is formed thinner than the Hall element 11, the disk drive motor is thinner than the conventional case where the Hall element 11 is directly arranged on the facing surface of the field magnet 5. Can be Therefore, the gap between the field magnet 5 and the print coil 3 is reduced, and the magnetic flux density is increased accordingly, so that the torque is increased.

(Embodiment 2) FIGS. 5 and 6 are enlarged views of a Hall element mounting portion showing Embodiment 2 of the present invention. As shown in FIG. 5, the magnetic body 4 is located between the print coil 3 and the auxiliary yoke 6 within the magnetic field range of the field magnet 5 and outside the range of the direct magnetic flux of the field magnet 5, that is, It extends to a position outside the outer circumference of the rotor 2 or the outer circumference of the bracket 1, and the extended portion is inserted into the groove 1b formed in the convex portion 1a of the bracket 1. The Hall element 11 is arranged so as to face the surface of the magnetic body 4 extending to the outside of each outer circumference. Other configurations are the same as those in the first embodiment.

According to this embodiment, since the magnetic body 4 is inserted between the print coil 3 and the bracket 1 and in the groove 1b formed in the convex portion 1a of the bracket 1,
Compared to the case where the magnetic body 4 is provided between the print coil 3 and the rotor 2 in the first embodiment, the gap between the field magnet 5 and the print coil 3 can be made closer, and the magnetic body 4 Print coil 3 and bracket 1
In this embodiment, all the magnetic flux from the field magnet 5 can cross the print coil 3 as compared with the case where the magnetic flux is shielded by the magnetic body 4 even in the first embodiment. As a result, the disk drive motor can be made thinner than in the first embodiment, and the torque of the motor can be further increased.

(Third Embodiment) FIGS. 7 and 8 are enlarged views of a Hall element mounting portion showing a third embodiment of the present invention. In the present embodiment, as shown in FIGS. 7 and 8, the magnetic body 4 is placed between the print coil 3 and the auxiliary yoke 6 or between the field magnet 5 and the print coil 3 within the magnetic field range of the field magnet 5. To a position outside the range of the direct magnetic field of the field magnet 5, that is, to the outer circumference of the rotor or the outer circumference of the bracket 1 and fixed to the print coil 3 side, and between the print coil 3 and the auxiliary yoke 6. In the case where the Hall element 11 is inserted into the groove 1b formed in the convex portion 1a of the bracket 1, the Hall element 11 can be fitted into the print coil 3 outside the outer circumference of the rotor 2 or the outer circumference of the bracket 1, respectively. The hole 3b is formed and the Hall element 11 is fitted into the hole 3b. The other configuration is the first embodiment.
Is the same as.

According to this embodiment, in addition to the function and effect of the second embodiment, the Hall element 11 is arranged from the surface of the printed coil 3.
The amount of sticking out is reduced.

(Embodiment 4) FIGS. 9 and 10 are enlarged views of a Hall element mounting portion showing Embodiment 4 of the present invention. In this embodiment, as shown in FIGS. 9 and 10, instead of the magnetic body 4 of the first embodiment, the field magnet 5 in the outer peripheral direction from the magnetic field range of the field magnet 5 with respect to the surface of the printed coil 3 is used. To a position outside the direct magnetic field range, that is, to a position outside the outer periphery of the rotor 2 or the outer periphery of the bracket 1, by applying a coating material containing magnetic powder 14 as a main component to the field plate by printing. The Hall element 11 is arranged so as to face the surface of the magnetic powder 14 printed up to a position away from the direct magnetic flux of the magnet 5. Other configurations are the same as those in the first embodiment.

The paint containing magnetic powder 14 as a main component used in this case is 60% to 80% of magnetic powder in resin softened by an organic solvent, and magnetic powder 14 is applied. The position is the surface of the gap between the coil bodies 3a of the print coil 3 as in the magnetic body 4 of FIG. If the content of the magnetic powder 14 in the paint is 60% or less, the magnetic flux transmission rate is weak, and
If it is 0% or more, the strength of the coating film is insufficient. Other configurations are the same as those in the first embodiment.

According to the present embodiment, the magnetic powder 14 is applied to the surface of the print coil 3 instead of the magnetic material, so that the same effect as in the first embodiment can be obtained, and the disk drive can be used. The motor can be made thinner and the torque can be increased.

(Embodiment 5) FIGS. 11 and 12 show Embodiment 5 of the present invention, FIG. 11 is an enlarged view of a Hall element mounting portion, and FIG. 12 is a plane of a print coil, a field magnet and an auxiliary yoke 6. It is a figure which shows the above relative positional relationship.

In this embodiment, as shown in FIG. 11, without providing the magnetic body 4 and the magnetic powder 14 in Embodiments 1 to 4,
The outer diameter of the disk-shaped auxiliary yoke 6 is made larger than the outer diameter of the rotor 2, and the enlarged portion is formed into a flower-shaped convex shape 6a as shown in FIG. 12, and the print coil 3 facing the surface of the convex shape 6a is formed. A hole 3b into which the Hall element 11 can be inserted is formed in the portion, and the Hall element 11 is inserted into the hole 3b. Other configurations are the same as those in the first embodiment.

In this case, as shown in FIG. 12, the number of convex shapes 6a obtained by increasing the outer diameter of the auxiliary yoke 6 is the same as the number of magnetic poles of the field magnet 5, and the outer diameter of the auxiliary yoke 6 is The outer diameter of the base end to be increased is the same as the outer diameter 6c of the field magnet 5. Further, holes 6b at equal intervals are opened on the surface of the auxiliary yoke 6 so as to correspond to the field magnets 5.

According to this embodiment, by increasing the outer diameter of the auxiliary yoke 6 to a position outside the outer diameter of the rotor 2, the leakage flux of the magnetic flux flowing from the field magnet 5 toward the auxiliary yoke 6 is reduced. The Hall element 11 attached to the outer diameter of the rotor 2 via the auxiliary yoke 6
And the magnetic pole can be detected.

Further, the holes 6b are provided at equal intervals along the inner diameter 6d of the auxiliary yoke 6, and the outer peripheral shape is formed in the convex shape 6a as many as the number of magnetic poles of the field magnet 5. The magnetic field applied to 6 is concentrated on the outer periphery of the magnetic field to facilitate the detection of magnetic poles. Further, the holes 6b provided at equal intervals in the auxiliary yoke 6 can efficiently cross the magnetic flux with respect to the coil.

In addition to the effects of Embodiments 1 and 2, the auxiliary yoke 6 of the auxiliary yoke 6 can be formed without fixing the magnetic body 4 to the print coil 3 or printing on the surface of the print coil 3 with magnetic powder. Since the purpose of detecting the strength of the magnetic flux can be achieved only by locally increasing the outer diameter, the disk drive motor becomes the thinnest, the motor torque is increased, and furthermore, the manufacturing is simplified, The cost can be reduced.

[0037]

According to the disk drive motor of the present invention, as an effect according to claim 1, the field magnet is provided through the magnetic body extending from the magnetic field range of the field magnet to the outer peripheral direction thereof. The magnetic flux can be detected by the Hall element provided at a position outside the direct magnetic field range. Further, since the magnetic body can be formed thinner than the Hall element, the gap between the field magnet and the coil can be narrowed, so the gap is reduced accordingly and the total length of the motor is shortened. In addition, the torque of the motor can be increased by reducing the gap. further,
By using the print coil, the wiring pattern for the Hall element can be provided on the same surface as the coil section, so that it is not necessary to provide a substrate for the wiring section for the Hall element, and it can be a low-cost component. it can.

As an effect according to claim 2, by applying a paint containing magnetic powder as a main component to the surface of the print coil by printing, the gap between the print coil and the field magnet or the auxiliary yoke is narrowed. Therefore, the torque of the motor is further increased and the total length is further shortened.

According to the third aspect of the present invention, the magnetic flux generated by the Hall element is located at a position outside the direct magnetic field range of the field magnet without using a magnetic substance or magnetic powder, only by increasing the outer diameter of the auxiliary yoke. Since it can be detected, it can be manufactured at a low price.

[Brief description of drawings]

FIG. 1 is a sectional view of a disk drive motor showing a first embodiment of the present invention.

FIG. 2 is a plan view of the print coil in FIG.

FIG. 3 is an enlarged view of the Hall element mounting portion showing the first embodiment of the present invention.

FIG. 4 is an enlarged view of the Hall element mounting portion showing the first embodiment of the present invention.

FIG. 5 is an enlarged view of the Hall element mounting portion showing the second embodiment of the present invention.

FIG. 6 is an enlarged view of the Hall element mounting portion showing the second embodiment of the present invention.

FIG. 7 is an enlarged view of the Hall element mounting portion showing the third embodiment of the present invention.

FIG. 8 is an enlarged view of a Hall element mounting portion showing a third embodiment of the present invention.

FIG. 9 is an enlarged view of a Hall element mounting portion showing a fourth embodiment of the present invention.

FIG. 10 is an enlarged view of the Hall element mounting portion showing the fourth embodiment of the present invention.

FIG. 11 is an enlarged view of the Hall element mounting portion showing the fifth embodiment of the present invention.

FIG. 12 is a diagram showing a relative positional relationship on a plane of a print coil, a field magnet, and an auxiliary yoke 6.

FIG. 13 is an explanatory diagram of a conventional disk drive motor.

[Explanation of symbols]

 1 Bracket 2 Rotor 3 Print Coil 4 Magnetic Material 5 Field Magnet 6 Auxiliary Yoke 7 Rotating Axis 8, 9 Bearing 10 Disk 10a Disk Yoke 11 Hall Element 14 Magnetic Powder

Claims (3)

[Claims] 1. A field coil comprising a stator coil fixed to a bracket, and a field magnet fixed to the surface of the stator coil with an axial gap between the stator coil and the rotor. In a disk drive motor, in which a rotor with a fixed magnet is integrally fitted to the rotating shaft, and a bracket to which a stator coil is fixed rotates via bearings, the stator coil fixed to the bracket is formed as a print coil. At the same time, the field magnet and the auxiliary yoke are fixed to both sides of the print coil on the circumference of the rotor with an axial gap between them, and a magnetic material is placed on the print coil side between the print coil and the field magnet. And place one end within the magnetic field range of the field magnet, and the other end from the field magnet toward the outer circumference. By extending the field magnet to a position outside the range of the direct magnetic field and arranging a Hall element that faces the side surface of the extended end of the magnetic body and detects the intensity of the magnetic flux from the field magnet. A disk drive motor characterized by comprising: 2. A paint containing a magnetic powder as a main component is printed on the surface of the printed coil from a position within the magnetic field range of the field magnet to a position outside the direct magnetic field, and outside the range of the direct magnetic field. 2. The disk drive motor according to claim 1, wherein the Hall element is arranged so as to face the surface of the magnetic powder at the position. 3. The hall element is arranged so as to expand the outer diameter of the auxiliary yoke to a position outside the range of the direct magnetic field of the field magnet and to face the surface of the expanded portion. A disk drive motor according to item 1.